Dr. Tierney is board certified in Family Medicine and Primary Care Sports Medicine.  She graduated from the Milton S. Hershey Family and Community Medicine Residency Program in 2015, serving as chief resident from 2014-2015.  Following graduation, she did an additional year of fellowship training in Primary Care Sports Medicine through the Fairfax Family Medicine Program in Fairfax, VA.  Through her fellowship training, she worked with athletes at the high school, college and professional level.  Following her fellowship year, she pursued training in acupuncture through the Helm's Medical Institute and has been licensed in Medical Acupuncture since 2017.  

Dr. Tierney has many passions in life, but first is her family and spending time with her husband, two children and dog.  She enjoys hiking, skiing, running, spending time with her family/friends, traveling, trying new restaurants, DIY projects, music, seeing the world and learning about people.  She loves learning about her patients, their families, and working towards achieving health goals.  When she is not in clinic, you may find her exploring new hiking trails or coffee shops. 

Mary Tierney, M.D. Physician & Founder

Brenna Osmolinski, CRNP brings over a decarde of experience as a Family Nurse Practitioner in primary care, specializing in women’s health, hormones, and holistic wellness. She believes true healthcare begins with listening—looking beyond symptoms to understand the whole person and uncover opportunities for healing and balance.

Brenna earned her nursing degree from St. Luke’s School of Nursing and a Master’s in Nursing as a Family Nurse Practitioner from Bloomsburg University. As a Reiki practitioner, Brenna also incorporates a holistic perspective into her approach to care.

Through Direct Primary Care, she believes in offering personalized, relationship-centered healthcare designed to give you the time, attention, and support you deserve.  Brenna's goal is to help you understand your body, feel your best, and take an empowered role in your health.


Brenna Osmolinski, CRNP

At Walnut Grove Family Medicine, we value relationships with our patients.  Sharing medical concerns can be a time when patients may feel uncomfortable, scared or hesitant.  As a patient, you deserve the time and attention required to address all your concerns.  We believe in using science based research to guide treatment plans along with offering other supplementary modalities to guide care, when appropriate. For these reasons, we offer options to learn to stay healthy including meal guides, injury prevention and other community services to assist you in your health and life goals.  We hope, that as a patient at Walnut Grove Family Medicine, you feel listened to and apart of the family.  

Why We Do what We Do.